Hairline mask



FIG. 1 is a perspective view of a hairline mask showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is another perspective view thereof, in condition of use.

The broken lines depict environment only and form no part of the claimed design. 

CLAIM The ornamental design for a hairline mask, as shown and described. 